1. Field of the Invention
The present invention relates to a machine for processing a workpiece, while not marring surfaces of the workpiece. The invention more particularly concerns a machine for producing an element of a decorative product having a specific edge shape.
2. Discussion of the Background
Previously existing machines which produce decorative designs on a piece of material, such as wood, to create a molding have a number of shortcomings which result in marred or unappealing surface variations of the decorative product. Ideally, a machine that imparts a functional or decorative design onto a piece of wood in the creation of molding, should provide the lowest possible amount of undesirable surface variations or marring on any surface of the molding including the decorative surface. Some, but not all, marred surfaces can be re-worked, such as by sanding, to lessen the effect of the marring.
Prior art machines that produce molding accept a piece of wood or other workpiece onto a stationary bedplate. The workpiece is secured to the stationary bedplate by driving rollers. The driving rollers press the workpiece against the stationary bedplate. The driving rollers then rotate thus causing the workpiece to translate or move into the machine. While the workpiece moves, its lower surface rubs against the stationary bedplate. As the workpiece is introduced into the machine at least one surface of the workpiece is shaped by a cutter so as to produce an assembly profile. As the workpiece proceeds through the machine, its leading end comes into contact with one or more additional drive rollers. The force applied by the rollers must be sufficient to propel the workpiece through the machine by rotary action of the drive rollers, and usually results in the propelled surface being marred by the drive rollers. Further, unless the drive rollers are perfectly synchronized with one another, one of the rollers will push or pull the workpiece relative to the other roller, thus causing one of the rollers to move relative to the workpiece. The relative motion results in uneven machining and marring, or even destruction, of the workpiece. Still further, the movement of the workpiece relative to the stationary bedplate causes a stick/slip situation in which the molding moves in a discontinuous fashion still further causing the drive rollers to move relative to the workpiece thus causing surface damage to the molding. These cutting machines of the prior art also damage another surface of the molding in that the decorative surface of the molding that is in contact with the stationary bedplate is subject to marring and scratching due to the surface sliding across the stationary bedplate.
The lengths of molding which can be accepted in the machine and secured must have a minimum length which is equal to the distance between adjacent drive rollers. Otherwise, a workpiece shorter than the minimum length will not be fed through the machine. Such a limitation restricts the use of relatively short length moldings and produces relatively large amounts of scrap material. The scrap material often arises as the workpiece enters the cutting area from the leading edge of the workpiece from the time it first contacts the cutter until the time that it first contacts the closest drive roller to the exit side of the cutting area, causing the scrap material at the leading end of the workpiece for a distance equal to the distance from the cutter to the first drive roller at the exit of the cutting area. Scrap material is also produced once the trailing edge of the workpiece leaves contact with the drive roller closest to the cutter on the inlet side, up to a point where the cutter cuts the workpiece. Thus, there is a need for a machine which produces molding that does not mar the surfaces of the molding product or waste such large portions of the workpiece's length.